Tube-mill.



G- C. HQWARD.

TUBE MILL.

APPHGATIGN man sums 7, 1913.

Patented July 13. 1915 INVENTOH 5 1 70410119 BY mig w-z IQTTUHIVEV WITNESSES.- 74 of, @445 W G'U'Z C. HOWARD, BE EVERETT, WASHINGTON.

TUBE-MEL.

Li ith-Wild.

To all whom it may concern Be it known that I, GUY C. HOWARD, a

citizen of the United States, residing at Everett, in the county of Snohomish and State of Washington, have invented certain new and useful Improvements in 'llube- Mills, of which the following is a specification.

This invention relates to improvements 1 in apparatus for the production of fiber fromwood or similar substances and particularl'y to improvements in the devices heretofore patented or applied for by me in which a reduction mill of the tube mill type 5 is utilized to obtain the required disinte gration. Said patents and applications are as follows: United States Patents Nos. 997,064., dated Julyd, 1911 and 1,039,286, dated Sep. 24, 1912; and patent applicatmn,

' Serial No. 717,035.

' The object of the present invention is the provision of improved devices for effecting the discharge of the product of a null to automatically regulate the level of the mate- 5 rial under treatment within the mill to a des ired height as predeterminately adjusted by th e operator.

It has been found by experiment in disintegrating woodfiber in a mill using balls so or pebbles as a reducing agent, that to assure a maximum reducing action on the material in its passage through the mill, the height of the" charge in the millthat 1s to say, the amount of water and fibrous ma- 85 lterial, must be kept within a certain range.

Too large a charge in the mill reduces the elliciency of the grinding forces and too low a charge reduces the capacity and ou put. The best results are obtained when the 40 lcharge is of the proper fluidity and approximately fills the interstices of the pebble load. Thus, when the mill is in revolution the ebbles tend to climb upon the up sideof the mill while a liquid bath free from pebbles is maintained on the down side of the mill. An opportunity is thus afforded for the material to partially free itself from the pebbles at each revolution, prevents matting of the fibers and assists in the lprogress of the material through the mill. The present invention consists in the novel construction of an adjustable discharge regulator, and the combination and adaptation of the same to a tube-mill whereby the deisired level of the charge within a mill will be automatically maintained, as will be fully Specification of Letters Eater 1t. Patented uly 13, 1915 Application filed June '7, 1913. Serial No. 772,23 i

described in the following specification,

illustrated in the accompanying drawings,

andfinally set forth in the appended claims.

In said drawings, Figure 1' is a side ele- 50 vation of a tube-mill and devices embodying my invention.- Fig. 2 is a longitudinal section of the discharge end of a mill, as illustrated in Fig. 1. Fig. 3 is a cross-sectional view on the line 3-3 of Fig. 2-with the cas- 55 ing partly broken away. Fig. 4 is-a. horizontal sectional view taken on the axis of the mill. Fig.5 is a fragmentary view to an enlarged scale of the screen-plate and connected parts, shown partly in section. 7o

Referring to said views, the reference numeral 1 designates the cylindrical barrel of a tube-mill of the type described in my said prior patents. Heads 2 and 3 respectively form the opposite ends of the mill havingyzs,

each an axially arranged hollowgtrunnion 2 3 through which the material to be reduced isrespectively fed and discharged. The former trunnion is connected with a feed-hopper 4 while the latter trunnion communicates with discharge regulating appa-' ratus hereinafter described and. forming the particular subject matter of this application. Said trunnions are rotatably mounted in standards 5 of a supporting frame and the mill is rotated, as shown, by a power driven pinion 6 in engagement with a circular rack 7 ion the exterior of the mill. Within the mill in proximityof its discharge end is a screen-plate 8 spaced apart from said header 3 to afford a chamber 9 and formed with numerous apertures 10 adjacent its circumferential edge alfording communication between said chamber and the grinding compartment of the mill A plurality of radially directed ribs "11 integrally or otherwise rigidly connected to said plate divide said chamber into a number of segmental pockets extending from the periphery of the plate to a centrally arranged chambered hub 12. Certain of said ribs are extended, as at 11 into the trunnion 3 and terminate therein in chamfered edges 11 v r v The reference numeral 13 indicates an open receptacle rigidly secured to the frame 5 and formed with an aperture in its end wall 14 to receive the extremity of said trunnion 3. One 0]. both of the side walls 15 are provided with an adjustable outlet for the discharge of the ground material from. the mill and each comprises a rectangular opening from the top of the wall, its opposuperposed order. Said slides are desirably of metal plate and are rectangular in configuration so that when placed in operative elevated Willjliow backward from the inposition their adjacent edges meet and stop the How of material therebetween. The material discharged. from the mill overflows the topmost slide into a launder or other suitable receiver, not shown. A drain aperture is provided in the bottom of the receptacle which is normally closed by a screwplug 20.

The operation of the invention may be described as follows: The material to be ground, consisting of chipped Wood, "straw or other fibrous material, is introduced into the mill through the hopper 4 with a sup-- ply of water apportioned to obtainthe most e'liicient disintegrating action from the halls contained Within the barrel. As tr e material progresses through the mill it'is gradually reduced in size and additional water is introduced within the mill to maintain the proper degree fluidity suited to the best results. This water may be injected through pipe 18 extending through a stuffing-boX'lQ in the receptacle 13 and communicating with the interior chamber of said hub 12 whence radially directed tubes, not shown, may conduct the Water into the interior of the. mill. I

In the operation of the mill the material issues through the apertures 10 from the grmding chamber of the mill on the side of the screen-plate that is lowermost and flows into the chamber 9 Where it is elevated by being trapped y the ribs in said segmental pockets and carried by the continued rotation or the mill to the top of its cycle of revolution. On its elevation above the axis of the mill the material flows into the non apertured portion of the screen and finds its outlet through the trunnion 3 whence it flows into the receptacle 18 and overflows the strips. A portion of the material thus terior of the trunnion through its opening into the lower portion of the chamber 9 to be elevated again with the material therein upon the continued rotation of the mill.

The higher the level of material in the barrel of the mill, the larger the quantity that will pass through the screen and the greater the height such material will. assume in said segmental pockets above the overflow discharge and therefore the more force in the flow of discharging material and a larger quantity emitted from the discharge The height of the material in.

receptacle. the pockets above the discharge, constituting the effective hydraulic head, does not vary to a great degree whatever the height to which the slides 17 may be built up, as the in the mill by balancing the to the overflow is modified by a back .ard current from the trunnion into the lower pockets where an excessive quantity of material is being passed. The chief factor is the uniformity of discharge regardless of temporary conditions of feed or other causes within the mill making for uniform hgn quality of product and a maximum quantity of output. "5;. The provision of adischarge outlet above I the level ofthe discharge orifice, in this case the trunion 3 and the utilizatio hydraulic forces in. the discha material, provides a novel n' th taining practically uniform charge functions th In practical 0 ed the dea 1? the he occurs meet or the 1 does not flow 0 other outlet direct fectedby the variation in giavn o' umns of liquid and hence a time c. .ient introduced and other balancing factors that insure reasonably uniform results.

Discharge apparatus of the type described 5 l by.

'is particularlyv well adapted for use with mills having material of a light and bulky character and which require large amounts of Water for treatment. For most minerals or other material of a relativelyhigh specific gravity, the apparatus would unsui; ed, save for grinding asbestos rcclr down to its fibrous condition.

What I claim is:

1.. The combination of a adapted to treat Wet ma "al ing a discharge 0 in a i. devices for elevatnig said .l'fiadollftl abovesaid orifice to obtain a hydraulic head the for to cause the material to flow by gravity through said orifice, and a receptacle into which said material is discharged having an outletadjustable in height above said orifice to regulate the said hydraulic head and there- 'by govern the outflow of material through the mill.

2. The combination of a rotatable mill adapted to treat Wet material, having a dis charge orifice in its axis of rotation, a screen-plate dividing said mill into a treat- 20 'ing compartment and a discharging chamtherefor to cause it to flow by gravity 1 5 throu h said orifice, a receptacle communicative y connected to said orifice to receive 'said discharge material having an outlet above the bottom of said orifice.

3. The combination of a rotatable mill 3o t of said orifice.

adapted to treat wet material, having a discharge orifice 'in its axis of rotation, a screen-plate dividing said mill into a reating compartment and a discharging chamber, said plate being provided with radially directed ribs adapted to elevate the material above said orifice to obtain a hydraulic head therefor to cause it to flow by gravity through said orifice, a receptacle communicatively connected to said orifice to receive said discharge material having an outlet. ad-

ustable at various heights above the bottom 4:. In combination with a rotatable mill having a hollow trunnion afiording the discharge passage of the mill, a screen-plate adjacent said trunnion provided with radial ribs for elevating the material abdve said orifice, said ribs having their inner ends entered Within said trunnion, of areceptacle rigidly secured relative to the rotatable portions of said mill and provided with an outlet above the bottom of said orifice.

5. In a rotatable mill for treating wet material, discharge apparatus therefor consisting in a trunnion having a passage therethrough in the axis of rotation of the mill, a non-rotative receptacle to receive the discharge of material from said passage having its outlet above the bottom of said orifice,

and means operable by the rotation of the elevated to obtain an effective hydraulic head for the discharge of said material from said outlet.

6. A rotatable mill for treating wet material having a compartment in which the material is treated, a screen-plate at one end of said compartment affording a chamber to receive the material for discharge, a hollow discharge trunnion in the axis of the mill communicating with said chamber, and a plurality of radially arranged ribsin said chamber extending into said trunnion whereby said material is elevated above said trunnion to obtain a hydraulic head therefor to cause the material to flow by--gravity throughsaid trunnion, and a receptacle into which said material is discharged, having an outlet adjustable at various elevations above the bottom of said trunnion.

7'. A rotatable mill having, in combination, a compartment in which the material is treated, a chamber at one end thereof, a screen intermediate said compartment and said chamber, a hollow discharge trunnion communicating"with said chamber, and a plurality of radial ribs having their inner ends extending within said trunnion for elevatin .the material above said trunnion.

8. n combination with a rotatable mill, a compartment in which the material is treated, a chamber at one end thereof, a screen intermediate said compartment and said chamber, a hollow discharge trunnion communicating with said chamber, and a plurality. of radial ribs for elevating the material above said trunnion, of a receptacle exterior of said discharge trunnion having its outlet elevated above the level of the bottom of said trunnion.

9. In combination with a rotatable mill having a compartment for the treatment of material provided with a feed inlet at one end, a screen at-the opposite end of said compartment affording a chamber, a trunnion in the axis of the mill formed with a discharge passage communicating with said. chamber, said screen having a hub extending within said trunnion, and radially disposed ribs dividing said chamber into a plurality of segmenta shaped pockets, of a receptacle adapted to receive the discharge material from said trunnion having its outlet elevated above the level of the bottom of said trunnion.

1-0. The combination of a rotatable mill adapted to treat wet material, said mill having a discharge orifice in its axis of rotation, devices for elevating said material above said orifice to obtain a hydraulic head therefor to cause the material to flow by gravity through said orifice, and a receptacle into which said material is discharged having an outlet above said orifice to govern the outflow of material through the mill.

Signed at Oregon City, Oregon, this 21st day of May, 1913.

' GUY C. HOWARD. Witnesses:

Fnaonmo A. OLMSTED, E. PETERSON. 

